Nortel BNT L2/3 Switch and ESX4.1

Hi,
I hope someone can advice on this as I am at a loss with this.
I have installed ESX4.1 onto 3 blades (IBM HS21) and Windows onto another 2 Blade (also HS21) inside an IBM E Class Chassis.
The are all part of a flat network, and no VLan was configured (yet).

I can ping the Windows blades from another PC and also ping the blades internally between each other.
I cannot ping the ESX blades, they can also not ping anything else or each other.

I read various articles about setting up untagged ports and also trying a vlan that not used as a PVID and tagging the vswitch. I tried this but still cannot get any access to the ESX blades from anywhere.